1. Field of the Invention
This invention pertains generally to directed light fabrication processes, and more particularly to a device which provides uniform distribution of gas-carried material powder within a directed light fabrication system.
2. Description of the Background Art
Fabrication of three-dimensional solids by means of directed fabrication, such as directed light fabrication (DLF), involves injecting powders into a high energy density moving beam, such as a laser light beam. The powders are carried by a stream of gas, commonly argon, to the focal point of the laser beam wherein material fusing occurs. The gas provides a non-reactive carrier for the particles of the powder which are to be fused into a solid. In practice, though, the powder is often injected non-uniformly about the beam resulting in a build-up from the fused powder material that is also of non-uniform structure. The lack of uniformity is particularly noticeable when the laser beam changes direction, thereby causing a different orientation of powder injection relative to the beam motion. This lack of uniformity in the resultant solid due to the improperly distributed powders becomes even more pronounced when fabricating alloy solids from a combination of powders.
Achievement of a uniform finished structure therefore requires uniformity of powder injection. The multiple feed powder splitter in accordance with the present invention when used with a multiple-outlet nozzle for powder disbursement satisfies that need, as well as others, and overcomes deficiencies in current powder feed techniques.